It is known that many cephalosporins are either not absorbed or not readily absorbed in the gastrointestinal tract, 7-(2-thienylacetamido)cephalosporanic acid, for example. Such compounds are usually administered parenterally in order to achieve high serum concentrations. It is therefore advantageous to have derivatives of cephalosporins a high percentage of which are absorbed on oral administration and produce their antiobiotic effect.
The new acylthiomethyl cephalosporin esters of this invention are more readily absorbed from the gastrointestinal tract and then are readily hydrolyzed to the free cephalosporin thereby providing a high concentration of antibiotically active substance.